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Abstract: Background: Proven medical therapy is under-prescribed in heart failure (HF) for various reasons. Cardiac resynchronization therapy (CRT) is of proven value in selected patients with HF; however, the degree of benefit in those without the optimal therapy is not clear. Methods: This is a retrospective study comparing the effect of CRT in 30 patients without optimal combination therapy (group 1; 10 (33%) without ACEi or equivalent and 25 (83%) without beta-blockers) to an age, sex, ejection fraction (EF) and New York Heart Association (NYHA) class matched control but with the combination (group 2; n =30) at baseline. All patients were in NYHA class III or IV with EF ≤35% and QRS interval≥120 ms. Echocardiographic examination and N-terminal pro-brain natriuretic peptide (NT pro-BNP) levels before and 3 months after CRT were compared between the two groups. The composite endpoints of HF hospitalization or death during follow-up were compared by Kaplan–Meier analysis. Results: There were significantly less improvement in EF (+4.0±2.5% vs +10.1±3.2%; p <0.05) and degree of reverse remodeling in group 1 after 3 months. Patients in group 1 had significantly higher level of NT pro-BNP levels at 3 months (2221±2001 pg/mL vs 1038±905 pg/mL; p <0.001) and higher rates of HF hospitalization or death (53.3% vs 23.3%; Log rank χ 2 5.52; p =0.019). Conclusion: Patients receiving CRT but without optimal medical therapy were associated with less echocardiographic and clinical improvement. Optimal medical therapy, if tolerated, before CRT is necessary. [Copyright &y& Elsevier]

Objectives: The present study aimed to examine whether diastolic and systolic asynchrony exist in diastolic heart failure (DHF) and their prevalence and relationship to systolic heart failure (SHF) patients. Background: Few data exist on mechanical asynchrony in DHF. Methods: Tissue Doppler echocardiography was performed in 373 heart failure patients (281 with SHF and 92 with DHF) and 100 normal subjects. Diastolic and systolic asynchrony was determined by measuring the standard deviation of time to peak myocardial systolic (Ts-SD) and peak early diastolic (Te-SD) velocity using a 6-basal, 6-mid-segmental model, respectively. Results: Both heart failure groups had prolonged Te-SD (DHF vs. SHF vs. controls subjects: 32.2 ± 18.0 ms vs. 38.0 ± 25.2 ms vs. 19.5 ± 7.1 ms) and Ts-SD (31.8 ± 17.0 ms vs. 36.7 ± 15.2 ms vs. 17.6 ± 7.9 ms) compared with the control group (all p < 0.001 vs. control subjects). Based on normal values, the DHF group had comparable diastolic (35.9% vs. 43.1%; chi-square = 1.48, p = NS), but less systolic asynchrony than the SHF group (39.1% vs. 56.9%; chi-square = 8.82, p = 0.003). Normal synchrony, isolated systolic, isolated diastolic, and combined asynchrony were observed in 39.1%, 25.0%, 21.7%, and 14.1% of DHF patients, respectively, and these were 25.6%, 31.3%, 17.4%, and 25.6%, correspondingly, in SHF (chi-square = 10.01, p = 0.019). The correlation between systolic and diastolic asynchrony, and between the myocardial velocities and corresponding mechanical asynchrony appeared weak. A wide QRS duration (>120 ms) was rare in DHF (10.9% vs. 37.7% in SHF) (chi-square = 16.69, p < 0.001). Conclusions: Diastolic and/or systolic asynchrony was common in 61% of DHF patients despite narrow QRS complex. The presence of asynchrony was not related to myocardial systolic or diastolic function. Systolic and diastolic asynchrony were not tightly coupled, implying distinct mechanisms. [Copyright &y& Elsevier]

Objectives: This study was designed to evaluate the role of cardiac resynchronization therapy (CRT) in heart failure (HF) patients with narrow QRS complexes (<120 ms) and echocardiographic evidence of mechanical asynchrony. Background: Cardiac resynchronization therapy is currently recommended to advanced HF patients with prolonged QRS duration. Echocardiographic assessment of systolic mechanical asynchrony has been proven useful to predict a favorable response after CRT. Methods: A total of 102 HF patients with New York Heart Association (NYHA) functional class III or IV were enrolled. Among them, 51 had wide QRS (>120 ms) and 51 had narrow QRS (<120 ms). Tissue Doppler imaging (TDI) was employed to select patients with systolic asynchrony (increased asynchrony index) in the narrow-QRS group. Clinical and echocardiographic assessments were performed at baseline and 3 months after CRT. Results: There was a significant reduction of left ventricular (LV) end-systolic volume in both narrow (122 ± 42 cc vs. 103 ± 47 cc, p < 0.001) and wide (148 ± 74 cc vs. 112 ± 64 cc, p < 0.001) QRS groups. Improvement of NYHA functional class (both p < 0.001), maximal exercise capacity (both p < 0.05), 6-min hall-walk distance (both p < 0.01), ejection fraction (both p < 0.001), and mitral regurgitation (both p < 0.005) was also observed. In both groups, the degree of baseline mechanical asynchrony determined LV reverse remodeling to a similar extent, as shown by the superimposed regression lines. Withholding CRT for 4 weeks resulted in loss of echocardiographic benefits. Conclusions: Cardiac resynchronization therapy for HF patients with narrow QRS complexes and coexisting mechanical asynchrony by TDI results in LV reverse remodeling and improvement of clinical status. The amplitude of benefit is similar to the wide-QRS group provided that similar extent of systolic asynchrony is selected. [Copyright &y& Elsevier]

Abstract: Background: Atrial function is an integral part of cardiac function which is often neglected. The presence of coronary artery disease (CAD) may impair atrial function. This study investigated if atrial mechanical dysfunction was present in patients with CAD by tissue Doppler echocardiography (TDI). Methods: Echocardiography with TDI was performed in 118 patients with CAD, and compared with 100 normal controls with comparable age and heart rate. Regional atrial function was assessed at the left (LA) and right (RA) atrial free wall and inter-atrial septum (IAS). The peak regional atrial contraction velocity of (V A) and the timing of mechanical events were compared. Results: The V A in the LA (5.0±2.6 Vs 7.7±2.6 cm/s), IAS (4.8±1.7 Vs 5.7±1.5 cm/s) and RA (6.8±3.1 Vs 9.2±2.9 cm/s) were significantly decreased in patients with CAD when compared with controls (all p <0.001). Patients with impaired systolic function (ejection fraction≤50%) had significantly lower V A in the LA and IAS than those with ejection fraction>50% (both p <0.001); and were lower in those with restrictive filling pattern (RFP) than non-RFP of diastolic dysfunction (both p <0.05). The V A in all the subgroups was lower than controls. In contrast, transmitral atrial velocity was unable to reveal any abnormality except in the subgroup with a RFP. The LA dimension, area and volume were increased in the disease groups, but were largely unchanged in the RA despite abnormal V A. The physiological inter-atrial delay for the onset and peak atrial contraction between the RA and LA were unaffected by CAD. Conclusions: The atrial contractile function in both atria was impaired in the presence of CAD, especially in the LA. This was detected even in patients with preserved systolic function or mild diastolic dysfunction such as non-RFP. Direct assessment of atrial velocity by TDI may better reflect atrial mechanical function than transmitral atrial velocity. [Copyright &y& Elsevier]

Efficacy of CRT for Mildly Prolonged QRS.. Introduction:Cardiac resynchronization therapy (CRT) has been shown to reverse left ventricular (LV) remodeling and improve symptoms in heart failure patients with wide QRS complexes; however, its role in patients with mildly prolonged QRS complexes is unclear. This study investigated if CRT benefited patients with mildly prolonged QRS complexes>120 to 150 ms and explored if the severity of systolic asynchrony determined such a response.Methods and Results:Fifty-eight patients (age 66± 11 years, 66% male) who had undergone CRT were studied prospectively. Of these patients, 27 had QRS duration between 120 and 150 ms (group A), and 31 had QRS duration>150 ms (group B). Tissue Doppler echocardiography and clinical assessment were performed at baseline and 3 months after CRT. Both groups had significant reduction of LV volume and increased ejection fraction,+dP/dt, and sphericity index (all P<0.05). These improvements were greater in group B and were explained by the higher prevalence of systolic intraventricular asynchrony. Significant reverse remodeling (reduction of LV end-systolic volume>15%) was evident in 46% of group A patients and 68% of group B patients. Improvement in clinical endpoints was observed in both groups (all P<0.01), although the changes in metabolic equivalent and New York Heart Association functional class were greater in group B. In both groups, systolic asynchrony index (TS-SD) was the most important predictor of reverse remodeling (r=−0.78, P<0.001) and was the only independent predictor in the multivariate model (β=−1.80, confidence interval=−2.18 to−1.42, P<0.001); QRS duration was not. A predefined TS-SD value>32.6 ms had a sensitivity of 94% and specificity of 83% to predict reverse remodeling. Improvement of intraventricular asynchrony after CRT was evident only in responders (P= 0.01).Conclusion:Improvement of LV remodeling and clinical status is evident after CRT in heart failure patients with QRS duration>120 to 150 ms. These responders are closely predicted by the severity of prepacing intraventricular asynchrony but not QRS duration.(J Cardiovasc Electrophysiol, Vol. 15, pp. 1-8, September 2004) [ABSTRACT FROM AUTHOR]

FUNG, J.W.H., et al.: Ablation of Nonsustained or Hemodynamically Unstable Ventricular Arrhythmia Originating From the Right Ventricular Outflow Tract Guided by Noncontact Mapping. --> Conventional activation or pacemapping is effective in guiding ablation of ventricular tachyarrhythmia originating from right ventricular outflow tract (RVOT). However, in selected patients with hemodynamically unstable or nonsustained tachycardia, noncontact mapping may be an effective alternative method to guide ablation in RVOT. Five patients with symptomatic hypotension during ventricular tachycardia (VT) or nonsustained tachyarrhythmia originating from the RVOT had radiofrequency ablation guided by noncontact mapping. All patients had a history of syncope and the tachyarrhythmias were refractory to antiarrhythmic therapy. Four patients had spontaneous sustained VT of a cycle length from 250 to 300 ms and one had symptomatic ventricular ectopic beats. Two patients were diagnosed to have arrhythmogenic right ventricular cardiomyopathy (ARVC). Sustained VT with hypotension was induced in two patients and nonsustained VT in three patients. Isopotential color maps were used to locate the earliest activation site of the tachyarrhythmia in RVOT. Three patients had tachyarrhythmia exit sites at the septal region and two at lateral region of RVOT. Low voltage area and diastolic activity were detected in the two patients with ARVC. Radiofrequency ablation guided by noncontact mapping was performed during sinus rhythm in all patients. The number of ablation attempts ranged from 1 to 14. After follow‐up for12 ± 5.8 months, there was no recurrence of tachyarrhythmia and syncope in all five patients. Noncontact mapping is a safe and effective alternative method to guide ablation of hemodynamically unstable or nonsustained ventricular arrhythmia originating from RVOT. (PACE 2003; 26:1699–1705) [ABSTRACT FROM AUTHOR]